There's nothing you could have done that would cause me to cease loving either of you. Will is myself, my own soul, and if I am not to have the keeping of your heart, then there is no other I would rather have that honor.

Contents

Biography

Early life

Jem was born in Shanghai, China, to his British father, Jonah Carstairs, and Chinese mother, Ke Wen Yu. He was raised at the Shanghai Institute, run by his parents. He lived there until he was twelve, when the Greater DemonYanluo, in retaliation for the destruction of his nest, killed his parents and tortured him by poisoning him with yin fen. Jem was in and out of consciousness and had become delirious, and by the time the Shanghai Enclave came to investigate, his parents were dead and he was already addicted to the drug.

Jem was rescued, though his dependence on the drug could not be cured. While Jem needed the drug for continued survival, regular doses of it was also deadly, so it became known since then that Jem would not live long.

When Jem arrived at the Institute, Will was also fairly new, having arrived half a year before him. The day he arrived, Will did not greet him with the others, so Jem was instead brought to the training room by Charlotte to meet him. When Will, in an attempt to dissuade Jem from befriending him, teased him about looking weak and close to death, Jem told him about his short lifeline. Jem then told him not to pity him and instead allow him to train with him and Will agreed.

Jem was the only one in the Institute to ever get through Will, who thought the curse he had on him would not matter with Jem as he was already dying. Almost a year after they met, Will asked Jem to become his parabatai. Jem initially refused, thinking Will deserved someone who would be able to look after him for a long time. However, the insistent Will wagered that if he could successfully get Jem's sword away from him, they would be blood brothers. Jem agreed and lost the bet. A year later, when they were both fourteen, they underwent the parabatai ceremony and have been inseparable since.

When he was fifteen, the demon Yanluo was finally slain. His uncle, Elias, invited Jem to move to Idris with him, though he refused so he could remain with Will. Around this time, Jem had also asked Will to promise him to stop looking for a cure for him.

Tessa and Mortmain

Jem was seventeen when he first met Tessa Gray. He and Will were investigating the death of the mundaneEmma Bayliss, which led them to the Dark Sisters, though Jem was not part of the raid on their house since he was too ill. Instead, he met Tessa the evening after Tessa's rescue, when she came into his room while he was playing the violin. He first mistook her for Will but didn't mind finding her at all. The two talk for a while, mainly about losing their parents, before a drunken Will arrived and Jem burst into a fit of coughing.

The following day, Jem and Will were sent to the Dark House to further inspect it. There, they found the body of the Dark Sisters' clockworkservant, which seemingly woke under Jem's touch. The creature warned them of some unknown danger before shutting off again. They brought the clockwork girl back to the Institute to be studied by Henry.

Over the course of the next few days, Jem worked closely with Will and Tessa on their investigations. He was particularly good to Tessa, mostly to make up for Will's misbehavior. Jem tried to help Tessa understand Will and adjust to London. He also guided Tessa while she learned of the Shadow World, telling her of vampires, after she met Camille Belcourt and had to Change into her. He also tried to help her understand her own warlock power.

When Tessa ran off into the London Institute after being upset by Will, Jem found her and took her for a walk. He took her to a bridge that wasn't visited that often because it didn't have a great view. He told her that this was his favourite place to visit when he needed to get away. They were suddenly attacked by two clockwork people, one of them being the Dark Sister's coachman. Jem fought them off, but became ill and started coughing when suddenly they were attacked by a whole army of the clockwork people. He and Tessa made it back to the Institute, by the time they got there Jem was extremely ill and could't respond to Tessa. Tessa couldn't open the Institute doors because she was not a Shadowhunter and so the two of them were attacked by the clockwork army. Will and the other Shadowhunters came out just in time and defeated the clockwork army, some of them escaping. However, Jem was injured and was taken back into the Institute.

Jem was treated and had to rest in bed, however, Will told Tessa that Jem would like to speak with her. He told her not to blame herself and then explained that he is addicted to demon blood and becomes ill when he needs more of it.

Jem showed Tessa the silver powder made from the demon blood, called yin fen, that satisfied his body's need for demon blood. Will bought the drugs for Jem, because Jem didn't not want to buy them himself, guilty of the fact that he needed the drugs in the first place. Without the drug, his natural Shadowhunter powers were weakened until he took more of the drug. Jem also had said that he took as little of the drug that he could as possible. Tessa noticed that after taking the drug, Jem's face seemed to have a light flush to it and his eyes seemed brighter and that the powder had a sweet smell to it, as she accidentally knocked the box where Jem kept the drug over while she and Jem were kissing. It was presumed that Jem snorted or sniffed the drug as opposed to smoking it as Will said that the smell of burning yin fen that a pack of werewolves were taking as sweet-sour scent to it as opposed to just the regular sweet smell. Jem witnessesed the werewolves dying from taking too much of the drug, and simply stood back and watched frightened. It was unknown how long the drug would take to take it's final effect on Jem.

While the Shadowhunters were attacking Alexei de Quincey's clan, Axel Mortmain visited the Institute. Will and Jem went out to hear what he had to say. He told them the location of the remaining Dark Sister that was supposedly going to help the Magister raise his clockwork army. The two of them left immediately, although Jem was unsure whether it was the right thing to do.

When they arrived they were attacked by the Dark Sister. She used her powers to set the building around them on fire, but they managed to kill her. Jem grabbed a cat that had been locked up in a cage. Once they had escaped they realized that it must had been all a trap and that Tessa and the group were in trouble. Will rode on ahead of Jem and began attacking the clockwork army. Jem arrived a little later and helped Will until the rest of the Shadowhunters arrived.

At the end of the book, Jem had revealed to have named the cat Church. Jem also comforted Tessa when she believed that because she was a warlock, she could not have children.[1]

Running out of time

Jem, Will and Tessa visited the York Institute to find out more about Mortmain's history and why he was so determined to kill Shadowhunters. Jem gave Tessa the Carstairs family ring as an engagement ring so she can pretend that she was a mundane who was preparing to Ascend and become a Shadowhunter. They met Aloysius Starkweather who showed them his spoils of war from killing Downworlders, making Tessa faint after seeing heads and body pieces of warlocks.

Jem proposed to Tessa, she accepted and he gave her his jade necklace as an engagement present. Sophie Collins was happy for them, because although she previously had liked Jem, she wanted him to be happy.[2]

Silent Brotherhood

It was revealed after a fight that Jem had been taking twice as much of the drug to make Tessa believe that he was getting better. Jem fell extremely ill, and there was no more yin fen for him, due to Mortmain stealing it all; Mortmain blackmaild Tessa into doing her binding until she did what he wanted: transformed in John Thadeus Shade.

Later, after Will went out to find Tessa, Jem fell more ill and told everyone that it was over, meaning that they should stop searching for a cure. It was thought that Jem died because Will's parabatai rune was bleeding and he felt their connection die.

It was revealed that he became a Silent Brother at the end of the book, and he was in fact Brother Zachariah. And as Brother Zachariah, he met Tessa once a year in the Blackfriars Bridge.[3]

Finding a cure

At last, 129 years after he was made into a Silent Brother, Jem was "cured" from his state, when the yin fen in him was burned away by the heavenly fire in Jace Herondale, whom he constantly looked after for being Will's descendant. Upon recovering, Jem was once again a mortal. The repressed emotions that did not bother him as a Silent Brother came flooding back, and he found himself unable to reclaim his Shadowhunter name and stead. Despite this, he chose to fulfill his duties and fight alongside the Nephilim in the Dark War. Though he was more than tempted to immediately go to Tessa and tell her everything, he chose to keep her away from the danger of the war.[4]

Only days after the war, Jem quickly decided that he would no longer be an active Shadowhunter, unable to bear the thought of being one without his parabatai. At their annual meeting at the Blackfriars Bridge, Jem reunited with Tessa, and the pair shared a kiss and agreed to explore the world together. They rekindled their relationship, and, eventually, their engagement.[4][3] The same day, the couple went to Tessa's flat in London, where Jem soon lost his virginity.[5]

Personality

Jem comes across as being kind, calm, and quite quiet, despite his bad past. He seems gentle and seems to be an unlikely Shadowhunter. However, he is a good fighter and extremely intelligent. He doesn't like to have people worrying about him and is especially secretive about his 'illness'. Will Herondale is usually the one to help him out and he tells Tessa Gray not to tell anyone how ill Jem was when she saw him become sick.

Physical description

Jem is described as being quite pale and having odd bright silver colored hair,
like an untarnished shilling. His eyes are said to be the same silver but with a gentle curve that hints at his parentage, and he has a fine-boned angular face, with a slight curve of his eyes. He looks youthful, partially because of his slightness. He is also tall, very slender and handsome too.

After he was cured of his illness, he is no longer pale as the color returns to his skin, his hair returns to black, with only a single silver streak remaining, and his eyes are dark brown with gold flecks.

Skills and abilities

Nephilim Physiology: Being Nephilim, Jem possesses a variety of enhanced physical and mental abilities granted to him by the blood of Raziel in his veins and also by the angelic Marks of the Gray Book. He also has power to perform tasks unique to their species, such as the ability to use and call on the power of angels for their seraph blades. This includes enhanced strength, agility, stamina, and coordination, which only improves over time and practice.

Runic Magic: Due to the angel blood in their veins. All Shadowhunters are able to apply runes on their skin without any real danger. These Marks, in turn, give varied effects that serve to benefit the wearer.

Healing: As a Silent Brother, Jem was capable of healing others.

Telepathy: Though unable to speak, he possessed the ability to communicate with someone through their mind and sift through it as well.

Special runes: Though he could bear some of the strange runes unique to the Brothers, the yin fen in his body still did not allow him to bear some of the more powerful ones.

Longevity: As a Silent Brother, Jem became immortal for over a century and lost it only after being burned by heavenly fire, making him once again mortal.

Possessions

Stele: Jem uses a stele to draw runes on his skin for healing, etc.

Cane: A dragon-headed and jade-topped cane. Back when Jem was still sick, James used a cane as a walking stick in case he needed it for support. The cane also served as his weapon, with a blade hidden in it.

Jade pendant: Jem has had two kinds of jade pendants:

A green stone pendant made of jade that was in the shape of a fist. It had been a gift from Will, who gave it to him thinking it would remind Jem of his home and make him feel less homesick. Jem hung it on a chain and wore it as a necklace.

A smooth, circular, whitish-green jade pendant. It had Chinese characters carved into it; the writing, taken from the I Ching, the Book of Changes, reads "When two people are at one in their inmost hearts, they shatter even the strength of iron or bronze." It had been a gift to his mother from his father. He gave it to Tessa when he proposed to her, and she has worn it since.

Yin fen box: Jem kept his supply of yin fen powder in a silver box with the lid depicting Kwan Yin, the goddess of mercy and compassion, that once belonged to his mother.

Relationships

Tessa Gray

“

I can offer you my life, but it is a short life; I can offer you my heart, though I have no idea how many more beats it shall sustain. But I love you enough to hope that you will not care that I am being selfish in trying to make the rest of my life—whatever its length—happy, by spending it with you. I want to be married to you, Tessa. I want it more than I have ever wanted anything else in my life.

Jem starts liking Tessa as soon as he meets her, though he doesn't tell her of his feelings until Clockwork Prince. As with everyone else, he's always kind to Tessa, who finds this very comforting. In Clockwork Prince, Tessa and Jem's affection for each other grows stronger as Jem occasionally takes Tessa to the important landmarks of London. At the end of the second book, Jem proposes to Tessa and she accepts. She loves Will too, but not knowing about the curse, believes him to be no good for her. Soon after, when Will comes back from Magnus's and tells her all about the curse and declares his love for her, she tells him of her engagement to Jem because even though she loves Will too, she can't bear hurting Jem. Will is shocked but asks Tessa if she loves Jem enough to keep him happy, and when she says yes, Will tells her not to tell Jem of Will's feelings for her.

At the start of Clockwork Princess, arrangements are being made of Jem's wedding to Tessa but in the midst of it all, Jem's illness starts to become worse. It turns out that since his engagement, he has started taking more of the yin fen so that he can be stronger around Tessa. This angers both Tessa and Will. When Mortmain buys up all the yin fen and then asks the Shadowhunters to hand over Tessa to him, and along with the letter, send a small packet of the drug, Jem tosses it in the fire and refuses Tessa to go, despite her protests and his weakening health. At the very end, after Jem has become a Silent Brother, he promises to meet Tessa once every year on Blackfriars Bridge, for one hour. They continue to meet like this until 2008, when Tessa suddenly finds Jem to have left the Brotherhood (it is nor specified how). Jem starts to ask Tessa if she would like to join him, but seeing that she's wearing Will's anniversary gift after all this time, he stops himself and abruptly turns away, thinking that Tessa doesn't love him the same way because she still loves Will. Tessa chases after him and shows him his mother's jade pendant hat she has been wearing all this time, too. She then invites him to see the world with her. Jem accepts, and they kiss on the bridge.

Will Herondale

“

Will closed his eyes. He could not hear Jem go, not anymore; he did not want to know the moment when he left and Will was alone, did not want to know when his first day as a Shawdowhunter without a parabatai truly began. And if the place over his heart, where his parabatai rune had been, flared up with a sudden burning pain as the door closed behind Jem, Will told himself it was only a stray ember from the fire.

When Jem first arrives at the London Institute, Will tries to intimidate him and drive him away by his moody attitude. But when he sees Jem to be unfazed and patient, he becomes friends with him immediately, surprising Charlotte. Through the years they spend together, Will helps Jem with his illness and Jem helps Will in facing the world. Will does not tell Jem of the curse put on him when he was 12, although Jem knows something is wrong. When they were 14, Will asked Jem to be his parabatai but Jem refused on the excuse that he was dying. But after loosing a bet with Will on a sword fight, he finally agreed. Will has always bought Jem the yin fen, because Jem couldn't face it himself. He cares for him when he is sick.

Even though Will loves Tessa, he gives her up for the sake of Jem. When Jem finds out, he is relieved instead of angry, and asks Will to go save Tessa and be with her an protect her and love her and keep her happy, for he can't do it himself.

When he leaves the Institute as a Silent Brother, Will is deeply heart-broken and falls into a depression for months, but finally recovers. After his marriage to Tessa, they both see Jem only occasionally.